/*
 * ProGuard -- shrinking, optimization, obfuscation, and preverification of Java bytecode.
 *
 * Copyright (c) 2002-2018 GuardSquare NV
 *
 * This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public
 * License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later
 * version.
 *
 * This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied
 * warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License along with this program; if not, write to the Free
 * Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 */
package proguard.optimize;

import proguard.classfile.*;
import proguard.classfile.util.SimplifiedVisitor;
import proguard.classfile.visitor.MemberVisitor;
import proguard.optimize.info.ReadWriteFieldMarker;

/**
 * This <code>MemberVisitor</code> delegates its visits to program fields to other given <code>MemberVisitor</code>
 * instances, but only when the visited field has been marked as write-only.
 *
 * @see ReadWriteFieldMarker
 * @author Eric Lafortune
 */
public class WriteOnlyFieldFilter extends SimplifiedVisitor implements MemberVisitor {
    private final MemberVisitor writeOnlyFieldVisitor;

    /**
     * Creates a new WriteOnlyFieldFilter.
     * 
     * @param writeOnlyFieldVisitor the <code>MemberVisitor</code> to which visits to write-only fields will be
     *        delegated.
     */
    public WriteOnlyFieldFilter(MemberVisitor writeOnlyFieldVisitor) {
        this.writeOnlyFieldVisitor = writeOnlyFieldVisitor;
    }

    // Implementations for MemberVisitor.

    public void visitProgramField(ProgramClass programClass, ProgramField programField) {

        if (ReadWriteFieldMarker.isWritten(programField) && !ReadWriteFieldMarker.isRead(programField)) {
            writeOnlyFieldVisitor.visitProgramField(programClass, programField);
        }
    }
}
